There have been known the technologies described in PTLs 1 and 2 as a speed control device of an electromotive vehicle.
PTL 1 discloses an automatic guided vehicle that moves according to instructions from its upper controller. The vehicle performs speed feedback control according to instructions from its upper controller. The vehicle is equipped with a counterrotating brake that exerts counterrotating torque on the electric motor.
PTL 2 discloses a method of collaboration between a regenerative brake and a mechanical brake in what is called a hybrid car, where an electric motor and an engine coexist. In PTL 2, a regenerative brake is applied in response to the travel of the pedal according to a rule and the deceleration is measured with an acceleration sensor. When the measurement result indicates that the regenerative brake does not generate a sufficient braking force, the mechanical brake compensates for the deficit.